The present invention relates to a semiconductor light emitting system, and in particular, relates to a system having a semiconductor light emitting element like a laser or a light emitting diode, and a microlens integrated with said light emitting element on a common semiconductor substrate.
Conventionally, light emitted by a semiconductor laser is focused by using a microlens which is located separately from the laser as shown in the Japanese patent laid open publication 187320/87.
However, that prior art has the disadvantages that it is difficult to locate a lens so that an optical axis of a laser coincides with that of a lens, since the lens is separated from the laser, and that the total size of the system including the laser and the lens is rather large, since the microlens has some size and weight.
Another prior art reference teaches the combination of a semiconductor laser and a waveguide lens. However, this prior waveguide lens has the disadvantages that a small spot less than several microns is impossible to form since an NA value (numerical aperture) higher than 0.2 with an efficiency higher than 10% cannot be formed therein, and that a beam is focused only in a lateral direction, but is not focused in a vertical direction. In the vertical direction, the beam is not focused, but is even diffracted, because of the small size of the waveguide in the vertical direction.